US President Donald Trump looks at Senate Majority Leader Mitch McConnell (L) as House Speaker Paul Ryan (2nd R) and Senate Majority Whip John Cornyn (R) look on during a meeting with Republican congressional leaders in the Roosevelt Room at the White House on June 6, 2017. (AFP photo)

Embattled US President Donald Trump has intensified a bitter fight with the leadership of his own Republican Party, blaming them for a legislative “mess” over raising the US debt ceiling.

Trump sought to blame Republican leaders in Congress for failing to reach an agreement on raising the cap on the amount the federal government may borrow, the latest in what have become regular criticisms of party leaders.

Trump said Thursday that Senate Majority Leader Mitch McConnell and House of Representatives Speaker Paul Ryan had failed to heed his advice to insert a debt ceiling measure into a veterans affairs’ bill which the president signed into law earlier this month.

“They … didn’t do it so now we have a big deal with Dems holding them up (as usual) on Debt Ceiling approval. Could have been so easy-now a mess!” he said in Twitter posts.

The US Treasury Department has said the debt ceiling must be raised by September 29, otherwise the government would not be able to pay its bills or borrow more money, which could hurt the US credit rating.

The Treasury Department said it is already using “extraordinary measures” to remain current on its spending obligations.

The fury among Senate Republicans toward Trump has been building since last month, following the president’s failure to rally the party around any version of legislation to repeal the Affordable Care Act, also known as Obamacare.

Among some establishment Republicans, there are signs that patience with Trump is wearing thin amid concerns about his ability to govern the country more than six months after taking office.

The relationship between Trump and McConnell has disintegrated to the point that they have not spoken to each other in weeks, according to more than a dozen people briefed by The New York Times.

Their initial uneasy governing alliance has turned into a feud of mutual resentment and sometimes outright hostility, the sources told the newspaper.

Senate Foreign Relations Committee Chairman Bob Corker told his constituents in Chattanooga, Tennessee earlier this month that Trump “has not yet been able to demonstrate the stability, nor some of the competence, that he needs to demonstrate in order for him to be successful.”

Last month, Trump suffered a humiliating blow as a small group of Republican lawmakers dealt him a stinging legislative defeat by voting against healthcare reform to replace Obamacare.

Trump’s refusal to draw a clear line between himself and white nationalist groups has been the latest source of growing tension within the Republican Party.